Addiction is one of the most common mental health problems there is: Drug use alone affects tens of millions of Americans, and that’s only the illegal ones. Even more people deal with addictions to other things – alcohol, caffeine, nicotine, food, and various behaviors. People who are familiar with addiction, and certainly the researchers who study it, may wonder whether their brains are fundamentally different from non-addicts, making them more prone to addiction’s grasp. Now, a new study offers an interesting answer to this very basic question.